On alot of the cdr i see advertised it says 80minutes audio (730mb)/ 700mb data- I have some avi's that are around 720mb- is it possible/advised to try and get them on 1 cd- and is that by enabling overburning in nero?

Try setting the overburn, I dont know if it will let you go that high. if it doesnt work, oh well, its only a cdr.

you can try and overburn past 700mb if your cd writer supports it but sometimes the overburned data can be unstable!